To perform the following procedures, the account you use must be delegated the following:

Exchange Organization Administrator role

For more information about permissions, delegating roles, and the rights that are required to administer Microsoft Exchange Server 2007, see Permission Considerations.

Also, be aware that to remove an OAB that is linked to a user or to a mailbox database, the recipient will download the default OAB until you assign a new OAB for that user. However, if you remove the default OAB, you must assign a different OAB as the default OAB. For more information about how to change the default OAB, see How to Change the Default Offline Address Book.